For example, erythropoietin (EPO) is upregulated by HIF-1α to boost erythropoiesis under anemic conditions or at high altitudes (Wang et al., 1995), while hypoxia exacerbates memory deficits in Alzheimer’s Disease (AD) mouse model by upregulating BACE1 (Sun et al., 2006). Here, EPO is linked to Alzheimer disease.